The invention relates to a method and a device for verifying the transmittance of a flat-glass substrate with a measuring device, with which light of at least one light source is guided from one side of the flat-glass substrate through the flat-glass substrate to the opposite side of the flat-glass substrate, where it is captured by at least one receiving unit and the transmittance of the flat-glass substrate is determined by means of a comparison between the intensity of the light emitted by the light source and the light incident upon the receiving unit.
In the manufacture of flat glass, a continuous transmittance must be achieved as one of various quality requirements. The thickness of the glass, for example, is another essential parameter. Particularly when using flat glass as solar glass, which is a special glass for thermal solar collectors and photovoltaics, a continuous transmittance has to be observed. In order to be able to use the incident solar radiation optimally, as high a transmittance as possible of the supported glass layer has to be ensured.